StackWalker::getInstance is currently specified to check for
StackFramePermission("retainClassReference“) due to an early review feedback .
Given it has only one target, it’s overkill to define a specific permission
type for stack walking use. This patch proposes to replace the StackWalker
permission check with RuntimePermission("getStackWalkerWithClassReference”) and
remove StackFramePermission class.http://cr.openjdk.java.net/~mchung/jdk9/webrevs/8176815/webrev.00/ Mandy
